You are showing the signs of coccyx pain which usually pains whenever it is under pressure like in sitting.
1 Go for ice cube massage
2 Use donut pillow to sit.
3 And rest.
3 take physiotherapy sessions of ultra sound massage which ll help you even more.
Sorry to hear that, but by end of spinal cord what you mean to say is tip of back where back meets hip. considering the above location
You need to make sure 2 things.
1. Is the pain at rest and does not progress > then it's only a bony pain and can be managed by a short Electronic modality known as Ultrasound (Physiotherapist). and providing soft comfortable cushions to your seating environment. if the bone (coccyx) is elongated then it has to be rectified surgically, performed by orthopaedic surgeon
2. If the pain progresses to lower limb particularly thigh , calf and beyond and worsens and makes difficult for you to walk. then it is suggesting of a nerve compression known as sciatic nerve, condition known as sciatica. which further can be managed by bit stretchings and strengthening of muscles of lower extremity and back.
Considering the location that you mentioned as anatomically perfect whcih is end of spinal cord (that leaves L4-L5) area it could be more of a spasmodic pain / pain due to weakness and over exertion / pain due to tightness of hamstrings. which further can be managed by following a regime of strengthening and stretchings and good nutritious diet
identify location and type and act accordingly , you might have to see an orthopedic depending upon the nature / cause or a therapist consultation will work.
RESPECT PAIN AND DON'T OVER EXERT / TWIST OFTEN. STAY HEALTHY
Please see an orthopedic doctor. Evaluate wether its coccxycodynia and then he will suggest you care to be taken. Accupuncture will also help but not before diagnosing the correct cause of pain. Hope this helps.